A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Analysis of imaging in pediatric bronchopulmonary foregut malformations with literature review: case reports

Background

Bronchopulmonary foregut malformation (BPFM) is an uncommon condition, with few case reports documented in both national and international literature. This scarcity underscores the importance of utilizing effective imaging techniques to improve our understanding and diagnostic precision concerning this disorder.

Case description

In the first case report, a neonate, born at full term and aged 15 days, presented with symptoms including dyspnea, coughing, wheezing, cyanosis, and vomiting. Initial diagnostic evaluations, which included chest radiography and upper gastrointestinal tract radiography, led to an erroneous initial diagnosis of a left-sided diaphragmatic hernia, accompanied by a suspicion of infection. In the second case report, another neonate, also born at full term but aged 5 days, exhibited symptoms such as coughing, choking, and mild vomiting. Utilizing a combination of computed tomography (CT) scans (plain, enhanced, and reconstructed), chest x-ray, and upper gastrointestinal tract radiography, the diagnosis of BPFM was accurately determined.

Conclusion

Comprehensive imaging examinations play a crucial role in reducing misdiagnosis and diagnostic oversights in cases of BPFM. Given its rarity, BPFM often manifests as a sequestered lung accompanied by gastrointestinal abnormalities. Hence, the integration of CT scans with gastrointestinal tract radiography can substantially improve diagnostic precision in such cases.

Familial pulmonary cysts: A clue to diagnose Birt-Hogg-Dubé syndrome: A case report and literature review

Birt-Hogg-Dubé syndrome (BHD) is an inherited autosomal dominant condition caused by germline mutations in the FLCN gene, mapped to chromosome 17p11.2. Typical manifestations include pulmonary cysts, spontaneous pneumothorax, fibrofolliculomas, and kidney neoplasms. This report details the case of a 56-year-old female non-smoker diagnosed with multiple pulmonary cysts, presenting with a history of recurrent spontaneous pneumothorax. A computed tomography (CT) scan of her daughter revealed similar pulmonary cysts, raising suspicion of BHD. Further abdominal enhanced CT revealed a left renal tumour and cutaneous fibrofolliculomas on her daughter's neck. Consequently, whole-exome sequencing confirmed an FLCN germline mutation in the patient and three relatives, establishing a diagnosis of BHD. This case highlights the importance of familial pulmonary cysts as a clue for diagnosing BHD, providing crucial insights into comparable clinical presentations.

Diffuse cystic lung disease caused by tuberculosis infection: Case series

Diffuse cystic lung disease (DCLD) is a complex disease that can be caused by various reasons. Although the chest CT scan plays a vital role in suggesting the etiology of DCLD, it is apt to lead to misdiagnosis simply based on the CT image of the lung. Here, we report a rare case of DCLD caused by tuberculosis and misdiagnosed as pulmonary Langerhans cell histiocytosis (PLCH). A 60-year-old female DCLD patient with a long-term smoking history was admitted to the hospital because of a dry cough and dyspnea, and the chest CT scan showed diffuse irregular cysts in both lungs. We considered the patient to be PLCH. To alleviate dyspnea, we chose to give her intravenous glucocorticoids. However, she developed a high fever during the use of glucocorticoids. We performed flexible bronchoscopy and bronchoalveolar lavage. Mycobacterium tuberculosis (specific sequence reads: 30) was detected in BALF. She was finally diagnosed with pulmonary tuberculosis. Tuberculosis infection is one of the rare causes of DCLD. We have discovered thirteen similar cases by searching Pubmed and Web of Science. For DCLD patients, glucocorticoids should not be used blindly unless the existence of a tuberculosis infection is ruled out. TBLB for pathology and bronchoalveolar lavage fluid (BALF) for microbiological detection are helpful for diagnosis.

Characteristic Chest Computed Tomography Findings for Birt-Hogg-Dube Syndrome Indicating Requirement for Genetic Evaluation

Background: Chest computed tomography (CT) findings are important for identifying Birt−Hogg−Dube (BHD) syndrome. However, the predictive power of classical criteria for chest CT findings is weak. Here, we aimed to identify more specific chest CT findings necessitating genetic examination for FLCN gene mutations. Methods: From June 2016 to December 2017, we prospectively enrolled 21 patients with multiple bilateral and basally located lung cysts on chest CT with no other apparent cause, including cases with and without spontaneous primary pneumothorax. All enrolled patients underwent FLCN mutation testing for diagnosis confirmation. Results: BHD was diagnosed in 10 of 21 enrolled patients (47.6%). There were no differences in clinical features between the BHD and non-BHD groups. Maximal cyst diameter was significantly greater in the BHD group (mean ± standard deviation; 4.1 ± 1.1 cm) than in the non-BHD group (1.6 ± 0.9 cm; p < 0.001). Diversity in cyst size was observed in 100.0% of BHD cases and 18.2% of non-BHD cases (p = 0.001). Morphological diversity was observed in 100.0% of BHD cases and 54.6% of non-BHD cases (p = 0.054). Areas under the receiver operating characteristic curves for predicting FLCN gene mutations were 0.955 and 0.909 for maximal cyst diameter and diversity in size, respectively. The optimal cut-off value for maximal diameter FLCN mutations prediction was 2.1 cm (sensitivity: 99%; specificity: 82%). Conclusions: Reliable chest CT features suggesting the need for FLCN gene mutations screening include variations in cyst size and the presence of cysts > 2.1 cm in diameter, predominantly occurring in the bilateral basal lungs.

A 17-Month-Old Male Infant With a Cystic Lesion of the Left Lung

CASE PRESENTATION

A 17-month-old male infant with history of an abnormal chest shadow in the left lung lower lobe was admitted to our hospital for the resection of the malformation. At 9 months of age, he was admitted to his local hospital because of a persistent cough. The chest CT scan in his local hospital indicated a cystic lesion in the left lung lower lobe associated with inflammation. However, no thoracic abnormalities were seen in antenatal ultrasonography, and no clinical symptoms were observed at birth. After anti-inflammatory treatments given to this infant, he achieved remission and was discharged from his local hospital.

Cystic lung disease

The term cystic lung disease encompasses a heterogeneous group of entities characterised by round lung lesions that correspond to cysts with fine walls, which usually contain air. The differential diagnosis of these lesions can be challenging, requiring both clinical and radiological perspectives. Entities such as pulmonary emphysema and cystic bronchiectasis can simulate cystic disease. High-resolution computed tomography (HRCT) is the imaging technique of choice for the evaluation and diagnosis of cystic lung disease, because it confirms the presence of lung disease and establishes the correct diagnosis of the associated complications. In many cases, the diagnosis can be established based on the HRCT findings, thus making histologic confirmation unnecessary. For these reasons, radiologists need to be familiar with the different presentations of these entities. A wide variety of diseases are characterised by the presence of diffuse pulmonary cysts. Among these, the most common are lymphangioleiomyomatosis, which may or may not be associated with tuberous sclerosis, Langerhans cell histiocytosis, and lymphocytic interstitial pneumonia. Other, less common entities include Birt-Hogg-Dubé syndrome, amyloidosis, and light-chain deposit disease. This article describes the characteristics and presentations of some of these entities, emphasizing the details that can help differentiate among them.

Airspace Enlargement with Fibrosis in a Young Heavy Smoker Mimicking Diffuse Cystic Lung Disease

The widespread use of computed tomography (CT) has led to the increased recognition of cystic lung lesions. Multiple pulmonary cysts can be observed in heterogeneous disorders called diffuse cystic lung diseases (DCLDs), which include pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, lymphocytic interstitial pneumonia, and Birt–Hogg–Dubé syndrome. Recently, airspace enlargement with fibrosis (AEF) has been recognized as an entity on the spectrum of smoking-related lung diseases. We report a young male heavy smoker presenting diffuse pulmonary cysts on chest CT with suspected DCLD. However, histopathological examination of the surgical biopsy specimen revealed dilated emphysematous cysts with prominent mural fibrosis, consistent with AEF.

Case Report: Misdiagnosis of Lung Carcinoma in Patients with Shrunken Lung Cyst After High Altitude Travel

Background

Lung cancer associated with cystic airspace is a rare disease, and the imaging understanding of lung cancer with cystic cavity is still unclear. Little is known in the literature on whether cystic lung cancer is caused by emphysema or ruptured bullae.

Case Reports

We report the case of a 50-year-old female patient after finishing a business trip in November 2021, when another chest CT demonstrated an unexpected reduction in the cyst, with a solid mural nodule on the posterior wall. The airspace of the cyst is only about 13 mm × 12 mm × 6 mm in size. The size of the mural nodule in the posterior wall is about 10 mm × 6 mm × 5 mm. The patient felt anxious due to suspicion of lung cancer. 2.5 months after the last chest CT, she accepted minimally invasive thoracoscopic surgery on the posterior basal segment of the left lower lobe. The postoperative pathology showed benign lesions.

Conclusion

For radiologists, it is important to recognize the process from lung cysts or bullae to LC-CAS, especially the morphological changes of the cyst airspace and the cyst wall, in order to identify the malignant features of lung cysts in time.

The Octopus Sign—A New HRCT Sign in Pulmonary Langerhans Cell Histiocytosis

Background: Fibrosis in pulmonary Langerhans cell histiocytosis (PLCH) histologically comprises a central scar with septal strands and associated airspace enlargement that produce an octopus-like appearance. The purpose of this study was to identify the octopus sign on high-resolution computed tomography (HRCT) images to determine its frequency and distribution across stages of the disease. Methods: Fifty-seven patients with confirmed PLCH were included. Two experienced chest radiologists assessed disease stages as early, intermediate, or late, as well as the lung parenchyma for nodular, cystic, or fibrotic changes and for the presence of the octopus sign. Statistical analysis included Cohen’s kappa for interrater agreement and Fisher’s exact test for the frequency of the octopus sign. Results: Interobserver agreement was substantial for the octopus sign (kappa = 0.747). Significant differences in distribution of the octopus sign between stages 2 and 3 were found with more frequent octopus signs in stage 2 and fewer in stage 3. In addition, we only found the octopus sign in cases of nodular und cystic lung disease. Conclusions: The octopus sign in PLCH can be identified not only on histological images, but also on HRCT images. Its radiological presence seems to depend on the stage of PLCH.

Pictorial review of computed tomography features of diffuse cystic lung disease

Diffuse cystic lung disease represents a diverse group of uncommon disorders that has been increasingly diagnosed due to the increasing use of computed tomography. It poses a frequent diagnostic challenge to radiologists due to the similar clinical and radiological features these diseases share. This pictorial review includes selected cases from the Hospital Authority New Territories West Cluster (NTWC) in Hong Kong from the past 3 years. It will illustrate the spectrum of diffuse cystic lung diseases, including some rarer entities in our locality, and identify the pertinent differentiating imaging features on CT. A flowchart to summarize these features is provided at the end to aid in diagnosis.

Nodular Pulmonary Amyloidosis Associated with Sjögren's Syndrome

Amyloidosis is a rare disease characterized by the deposition of abnormal proteins in extracellular tissues. We herein report a case with instructive radiologic features of nodular pulmonary amyloidosis associated with Sjögren's syndrome. A 67-year-old woman was referred to our department because of an abnormal chest radiograph. Chest computed tomography revealed multiple round cysts accompanied by calcified nodules. The patient was clinically diagnosed with primary Sjögren's syndrome and pathologically diagnosed with nodular pulmonary amyloidosis (light chain, kappa). Although multiple lung cysts have many etiologies, the presence of calcified nodules associated with multiple lung cysts is useful for narrowing down the differential diagnosis.

Pneumonia-related pneumatoceles in infants: CT assessment and image-guided treatment

Lung pneumatoceles represent a potential life-threatening complication of pneumonia in infants, especially when they do not spontaneously reabsorb. In this category of patients, scientific literature lacks and no consensus guidelines for management have been proposed. Imaging plays a key role in the diagnosis, characterization, and follow-up of pneumatoceles. Image-guided percutaneous drainage can be considered a safe and effective treatment in children, although it is not widely recognized in newborns and infants. The aim of this case series review is to describe the main CT features of complicated or persistent pneumatoceles in infants and to highlight the potential role of image-guided percutaneous drainage as an effective approach for their treatment. Successful management of four infants affected by pneumonia-related pneumatoceles with percutaneous drainage is presented.

Lymphangioleiomyomatosis and Langerhans cell histiocytosis - two case reports from our practice

Introduction. Lymphangioleiomyomatosis (LAM) and pulmonary Langerhans cell histiocytosis (PLCH) are the most common pulmonary cystic diseases. Although they differ in pathogenesis, they share several features. The aim of this paper is to present the similarities and differences between these diseases, as well as to describe two cases from our practice. Outlines of cases. The patient with LAM (43 y.) has pulmonary changes detected during regular examination within the underlying disease - tuberous sclerosis. Four years after starting therapy with everolimus she is still respiratory asymptomatic, a slight radiological deterioration of cystic changes is registered, the diffusion capacity is declining (for 12%). The second patient (23 y.) was admitted due to bilateral radiological lung changes and symptoms in the form of dry cough, quick fatigue and chest pain. Pathohistological examination of the transbronchial biopsy showed numerous large-core histiocytes, immunohistochemically positive for CD1a and S100, so it has been concluded that it is Langerhans cell histiocytosis. Cessation of smoking was advised. The follow-up examinations show withdrawal of symptoms and an orderly finding of lung function, chest HRCT indicates slight regression of changes. In the meantime, the patient gave birth to a healthy child, the pregnancy and prenatal period went smoothly. Conclusion. These diseases are extremely rare and in cooperation with other specialties should be distinguished from diseases that mimic lung cysts.

Cystic Lung Disease as a Sequela of Severe COVID-19: Case Series

Coronavirus disease 2019 (COVID-19) presented in December 2019 and has persisted since. The global pandemic has given rise to a novel acute disease process with a continually rapidly increasing prevalence of chronic disease and associated complications. There is minimal information on the long-term pulmonary complications of this disease. We present a series of 9 patient case reports and their respective imaging admitted with COVID-19 acute respiratory distress syndrome (ARDS) to highlight the cystic lung disease complications which may arise due to severity and disease progression. Our aim is to raise awareness of the sequela of COVID-19 ARDS, including its potentially catastrophic long-term consequences to the respiratory tract involving cystic lung disease.

Atypical pulmonary metastases in children: the spectrum of radiologic findings

Pulmonary nodules present a diagnostic challenge when they appear as atypical metastases in pediatric oncology patients. Chest computed tomography (CT) is the primary imaging modality for assessing lung nodules. In pediatric populations, Wilms tumor and osteosarcoma are the cancers most likely to produce pulmonary metastasis, both typical and atypical. This pictorial essay provides a thorough description of the specific radiologic features of atypical pediatric pulmonary metastases, and their pathogenesis and differential diagnosis. We also address diagnostic approaches to incidental lung nodules in healthy children found in the literature. Our aim is to help radiologists identify atypical lung metastases on CT, ensuring that children receive prompt, and potentially lifesaving, treatment.

A 63-Year-Old Woman With an Acute Exacerbation of Interstitial Pneumonia

CASE PRESENTATION

A 63-year-old, non-smoking Asian woman presented to our hospital due to abnormal findings on chest radiography. She had no history of dust exposure. Chest radiography and CT imaging showed patchy ground-glass attenuation (GGA) in the bilateral lower lung lobes, a ground-glass nodule in the right lower lung lobe (diameter, 9.8 mm), and some thin-walled cysts in both lungs (Fig 1). Thickening of the interlobular septa, mediastinal lymphadenopathy, and pleural effusion were not evident. Video-assisted thoracic surgery was performed for the examination of the nodule and the background lung disease, and the nodule was histologically diagnosed as lung adenocarcinoma. Simultaneously, the lung background showed diffuse lymphocytic infiltration in the alveolar septum and peribronchovascular interstitium (Fig 2). There were no symptoms suggestive of autoimmune diseases such as dryness, arthralgia, skin rash, or fever. The patient was followed up without treatment for the interstitial lung disease.

Early and Atypical Radiologic Presentations of Pulmonary Langerhans Cell Histiocytosis: A Report of Two Cases

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare, multi-systemic disease primarily affecting young male adults with a history of smoking. The two patients with PLCH in our report showed relatively early and atypical radiologic presentations at initial evaluation. On chest CT, PLCH presents variable radiologic features depending on the evolutional stage of the disease. Atypical CT features of PLCH may render precise radiologic diagnosis difficult and usually require lung biopsy for a confirmation of the diagnosis. Our case review is aimed at raising the awareness of radiologists on the atypical CT features of PLCH, to help make accurate radiologic diagnosis and prevent unnecessary and invasive diagnostic procedures.

CT findings of pulmonary cysts

Pulmonary cysts are thin-walled radiolucent lesions that may appear in a variety of uncommon disorders known as diffuse cystic lung diseases (DCLD) that essentially includes lymphangioleiomyomatosis (LAM), Langerhans cell histiocytosis (LCH), lymphocytic interstitial pneumonia (LIP), Pneumocystis jiroveci pneumonia (PJP), and Birt-Hogg-Dubé syndrome (BHDS). Moreover, they have been reported in several cases of coronavirus disease 2019 (COVID-19). The purpose of this review is to provide a practical approach for evaluating lung cysts when encountered on CT. We describe the imaging findings of DLCD emphasising their differences in terms of shape and distribution of the cysts, as well as their association with other findings such as nodules or ground-glass opacities, which may help in making a confident diagnosis. We also discuss the link between pulmonary cysts and COVID-19.

Not COVID-19, Don't Overlook Pneumocystis in Patients on Gefitinib!

Simple Summary

COVID-19 pneumonia can be confused with Pneumocystis jirovecii pneumonia (PJP) on computed tomography and is a source of misdiagnosis. This can lead to mistreatment and an increased risk of mortality. Gefitinib, a tyrosine kinase inhibitor anti-EGFR used in cancer therapy and corticosteroids, could increase the risk of PJP.

Abstract

An 82-year-old woman treated for advanced lung cancer with gefitinb was admitted to the emergency unit complaining of dyspnea. Chest computed tomography found abnormalities classified as possible diffuse COVID-19 pneumonia. RT-PCR for Sars-Cov-2 was twice negative. PCR for Pneumocystis jirovecii was positive on bronchoalveolar lavage. The final diagnosis was Pneumocystis jirovecii pneumonia. Therefore, physicians must be careful not to misdiagnose COVID-19, especially in cancer patients on small-molecule therapeutics like gefitinib and corticosteroids.

Pulmonary pneumatoceles in neonates

Pulmonary pneumatoceles were relatively common in neonates in the pre-surfactant era. In the current era of surfactant, noninvasive and gentle invasive ventilation there is a paucity of data on clinical characteristics and outcomes of pneumatoceles in neonates. The lesion generally resolves spontaneously, but a few cases follow a complicated course with formation of extensive and expanding lesions. To better understand the pathophysiology, clinical significance, natural history, complications, treatment options and prognosis of pulmonary pneumatoceles in neonates, an extensive research was performed on the databases of medical literature. The information collected in this review is important for the clinicians in decision-making, especially in the most difficult cases.

Interstitial Lung Fibrosis Imaging Reporting and Data System: What Radiologist Wants to Know?

The aim of this work is to review interstitial lung fibrosis Imaging Reporting and Data System (ILF-RADS) that was designed for reporting of interstitial lung fibrosis (ILF). Findings include pulmonary and extrapulmonary findings and is subsequently designed into 4 categories. Pulmonary findings included lung volume, reticulations, traction bronchiectasis, honeycomb, nodules, cysts, ground glass, consolidation, mosaic attenuation and emphysema, and distribution of pulmonary lesions; axial (central, peripheral and diffuse), and zonal distribution (upper, middle, and lower zones). Complications in the form of acute infection, acute exacerbation, and malignancy were also assessed. Extrapulmonary findings included mediastinal, pleural, tracheal, and bone or soft tissue lesions. The lexicon of usual interstitial pneumonia (UIP) was classified into 4 categories designated as belonging in 1 of 4 categories. Lexicon of ILF-RADS-1 (typical UIP), ILF-RADS-2 (possible UIP), ILF-RADS-3 (indeterminate for UIP), and ILF-RADS-4 (inconsistent with UIP).

Characteristics of primary Sjögren's syndrome related lymphocytic interstitial pneumonia

Objective

This paper is aimed at investigating the clinical characteristics of primary Sjogren’s syndrome (pSS) with lymphocytic interstitial pneumonia (LIP).

Methods

The demographic data, clinical manifestations, laboratory and radiological findings, treatment, and prognosis from 15 cases of pSS-LIP patients were retrospectively analyzed. The data were compared with t test, χ² test, and Pearson/Spearman correlation analysis.

Results

(1) Fifteen cases of patients with pSS-LIP are all females (100%). Compared with pSS with interstitial lung disease(pSS-ILD) patients, the incidence of dry cough, dental caries is higher in pSS-LIP patients. The incidence of shortness of breath, weight loss, and crackles is lower in pSS-LIP patients than that of pSS-ILD patients. (2) Compared with pSS-ILD patients, pSS-LIP patients had higher percentage of patients with ANA, anti-SSA52KD antibody, anti-SSA60KD antibody, and anti-SSB antibody, and the higher concentration of serum globulin. (3) Compared with pSS-ILD patients, the frequency of obstructive ventilation dysfunction is significantly higher and the frequency of diffusion dysfunction is significantly lower in pSS-LIP patients. (4) The most frequent HRCT findings in patients with pSS-LIP is cysts (100%), followed by ground-glass opacities (73.3%), nodular shadow (73.3%) among the pSS-LIP patients. Compared with PSS-ILD patients, the incidence of pulmonary nodule shadow is significantly higher in PSS-LIP patients, while that of grid shadow was significantly lower. (5) Compared with the baseline, the sum of the number, maximum diameter, and diameter of cysts in three levels of pSS-LIP patients showed an increasing trend after treatment. (6) Correlation analysis: The changes of ground-glass opacities were positively correlated with using GC or not, and those were negatively correlated with the dose of GC treatment. Besides, there is a positive correlation between the annual change rate of the maximum diameter of cysts (△Ømax1/t) and the use of CTX; there is a positive correlation between the annual change rate of the total diameter of cysts (△Øsum1/t) and the use of CTX.

Conclusion

To the patients of pSS-LIP, female were more common than male, and the onset of LIP was usually more insidious. Hyperglobulinemia and anti-SSA antibody were more prominent in patients with pSS-LIP. Pulmonary function showed the higher rate of obstructive ventilation dysfunction and the lower rate of diffusion dysfunction. The appearance of ground-glass opacities in pSS-LIP patients suggests that the infiltration of inflammatory cells increases, which may cause airway compression, the expansion of terminal bronchioles, and the formation of cysts. The more ground-glass opacities appear earlier, and the more appearance of new cysts later. Therapy with glucocorticoid may be effective on the ground-glass opacity during acute stage, and therapy with cyclophosphamide may be effective on the cysts during chronic stage. The heavier ground-glass opacity is at baseline, the more likely it will recur during maintenance treatment. So follow-up closely is needed.

Key Points • It is the first clinical study with more cases of patients with pSS-LIP. • Female and hyperglobulinemia and anti-SSA antibody were more prominent in patients with pSS-LIP. • Pulmonary function showed the higher rate of obstructive ventilation dysfunction and the lower rate of diffusion dysfunction. • Therapy with glucocorticoid may be effective on the ground-glass opacity during acute stage, and therapy with cyclophosphamide may be effective on the cysts during chronic stage.